Method of Designing and Producing Carbon Fiber Push Rods

ABSTRACT

A method of designing and producing a push rod uses continuous or discontinuous or chopped fiber pre-impregnated composite material wrapped around or surrounding a titanium tube, wherein the method allows push rod designers to machine several different push rod designs, lengths, diameters, and end types. The push rod would be shaped in a basic form (a blank having suitable length and stiffness), and then machined into a push rod. After the specific machining is performed, the oil drain hole is substituted with a titanium tube and the ends are capped with a suitable end for bearing against the rocker or the lifter, we then finish machining all surfaces. Push rods are then impregnated with Sodium Silicate to arrest fluid uptake.

RELATED APPLICATIONS

This application claims the benefit of U.S. provisional applications 62/752,595 filed Oct. 30, 2018, in the U.S. Patent and Trademark Office, titled “Method of Designing and Producing Carbon Fiber Push Rods” of inventor Bryan Gill, which is hereby incorporated herein by reference in its entirety.

BACKGROUND AND FIELD OF THE INVENTION

The present invention relates to automotive push rod manufacturing and methods of designing and producing composite push rods. More specifically, the present invention pertains to a new method of designing and producing a composite push rod using compression/vacuum molded, continuous or discontinuous chopped composite material to achieve a low-weight, high strength article that is machinable after being formed, along with a design process that allows several different designs to be machined from a shaped mold of composite material.

Automotive push rods are well known structures that work with the camshaft and rocker arms to open the engine's valves. High performance push rods are lightweight and high strength structures that can be specifically designed to increase the engine power and be sufficiently durable for competition or rigorous use. High performance and exotic engines are not the only engines in which may benefit from this technology. Push rods can be replaced for increased performance or in addition, better fuel economy. The present invention is directed to a new method of manufacturing and designing high performance push rods, which aims to increase performance thereof while maintaining a high degree of increased power and economy.

The present invention relates to a new method of designing and producing composite or metal based push rods, and in particular carbon fiber push rod designs that do not require specific molds of different sizes. Those with different requirements can be formed into a shape using a compression/vacuum molding technique. The resulting material is non-directional and conforms to the shape of the mold, wherein the chopped fibers are supported within a matrix in random directions to produce an overall quasi-isotropic material system. Using this material, the push rod design process benefits and can utilize the fact that this material system is machinable after being formed. Thus, the design method utilizes the chopped, continuous or discontinuous composite material to create a push rod blank that is adaptable to different diameters while minimizing lost material during the machining process. Once the push rod design is machined, the push rod can then be inserted with the titanium tube, drilled for oil hole if necessary and suitable ends are fitted to accommodate load transmitting bearing contact with the lifter or rockers.

The new design and manufacturing method with composite push rods using discontinuous or chopped fiber material, reduces material waste, reduces engineering design expense for each push rod design, and reduces the cost of composite push rods to consumers. Various molds are used to accommodate a plurality of push rod designs, lengths, diameters, and end types, whereby the resulting push rod blank from the single mold process is machined to a specific size and shape for the desired push rod, including, for example, a high strength elliptical shape from top to bottom. The resulting push rod then works with the camshaft to produce a high-performance push rod at a reduced weight compared to traditional metals of steel in the market.

The present invention diverges in design elements and method steps from the prior art, and provides an improvement to existing steel push rod designs and manufacturing methods. In this regard the instant invention substantially fulfills a needed improvement.

SUMMARY OF THE INVENTION

In the view of the disadvantages or limitations inherent in the known types of steel push rods and design and manufacturing methods present in the art, the present invention provides a new design and manufacturing method wherein the same can be utilized for producing a composite push rod surrounding a titanium core that reduces weight, resists deflection and wasted material to produce a lightweight, high performance push rod for competition or road use.

It is therefore an objective of the present invention to provide a new method of designing and manufacturing composite push rods, wherein the method includes a process of forming discontinuous or chopped fiber material into a push rod blank that is machinable to the end design of the given push rod.

Another objective of the present invention is to provide a design method for creating a composite push rod in which one mold can be utilized to create a push rod blank that accommodates a plurality of different push rod designs, whereby the final design is machined from the singly designed blank.

Another objective of the present invention is to provide design method of composite push rods that aims to increase efficiency to the end consumer, while still retaining the primary advantages associated with composite push rods (light weight, high stiffness, high strength, greater fatigue life, etc.).

Other objectives, features and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a completed push rod wherein an outer portion of carbon-based matrix material forms an elongated rod-like structure extending between end tip assemblies. FIG. 1 also shows a cut-away portion of shorter length, showing the structure of an inner titanium tube or substrate (1) within the jacket of composite material (2). The tube or substrate provides an oil passage or drain (4), and the completed push rod may also be provided with end tips (3) adapted for load-bearing contact with a cam or a cam follower.

DETAILED DESCRIPTION OF THE DRAWINGS

Reference is made herein to the attached drawings. Like reference numerals are used throughout the drawings to depict like or similar elements of the present method. For the purposes of presenting a brief and clear description of the present invention, the preferred embodiment will be discussed as used for creating a composite push rod blank using discontinuous or chopped fiber material and a design process that minimizes waste and weight. The figures are intended for representative purposes only and should not be considered to be limiting in any respect.

The present invention is a new design method and method of manufacturing for push rods using titanium and composite material, wherein the production of the push rod involves a forming process and the design method allows for multiple different push rod designs to be incorporated into a single manufacturing process. The design method reduces material waste and weight of the push rod for the end consumer, while maintaining the benefits associated with composite push rods. Specifically, discontinuous or chopped fiber reinforced plastic is used to create the push rod, wherein the chopped fiber is placed into a mold, compression molded into a formed shape, and then machined into a final push rod design. The use of chopped fibers and a forming process allows designers and fabricators to machine the final design from a larger push rod blank, which allows one push rod blank to be utilized for multiple push rod designs without individually engineering each push rod and creating a specific mold for each push rod design. This eliminates the traditional steel forging process and replaces it with a titanium core and a composite outer portion.

The present invention contemplates creating a composite push rod blank of carbon fiber, rather than forging steel; the present invention method utilizes a continuous or discontinuous chopped fiber compression molding process and a design process to produce a shape similar to steel push rod fabrication but with titanium and carbon fiber which leads to lower reciprocating mass, hence greater RPM optimization. A shaped push rod blank is created from the combination of several different push rod designs, which can then be machined down to the exact push rod design chosen by the end user. Push rod designs are overlaid onto one another in a design space to establish the shape of the push rod blank to be created from the discontinuous or chopped fiber material in a mold. The process can accommodate push rods of different diameter, length, end type and design, wherein the final product is matched to or intended to be connected between a lifter/camshaft assembly and a rocker arm.

Once released from the mold, the carbon fiber push rod blank is machined into a final design. A CNC milling machine or similar device is utilized to machine the larger push rod blank into the final push rod design.

The instant invention has been shown and described in what is the most practical and preferred method steps. It is recognized, however, that departures may be made within the scope of the invention and that modifications will occur to a person skilled in the art. With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function, steps, and manner of operation, assembly and use, would be apparent to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.

Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention. 

1. A method of designing and producing fully plated, titanium insulated composite push rods using a carbon based composite material, comprising the steps of: choosing one or a plurality of push rod designs; overlaying said push rod designs to determine a single push rod blank design; creating a reverse mold of said push rod blank design; compression molding a push rod blank using said reverse mold; and machining said push rod blank into one of said push rod designs.
 2. The method of claim 1, wherein choosing said push rod designs further comprises one or more of the steps of: determining diameter, length, end type and oil drain hole if necessary of said push rod designs prior to overlaying said push rod designs.
 3. The method of claim 1, wherein compression molding said push rod blank further comprises the steps of: heating composite material; communicating said composite material after heating into said mold; compressing said material in said mold using a press; preferably applying sodium silicate impregnation; and removing said material after cooling. 